Machine tool



Feb. 5, 192s. 1,700,974

A. BROWN MACHINE TOOL Filed July 1.9. 1927 2 Sheets-Sheet 1 Feb. 5, 1929. 1,700,974

A. BROWN MACHINE TOOL Filed July 19, 1927 2 Sheets-Sheet 2 Inqrzt'vr W e-SS (5 8 1, A/ a &%

Patented Feb. 5, 1929.

UNITED STATES PATENT OFFICE.

ARTHUR BROWN, OF CRANSTON, RHODE ISLAND, ASSIGNOR TO BROWN AND SHABPE MANUFACTURING COMPANY, A CORPORATION OF RHODE ISLAND.

MACHINE TOOL.

Application filed July 19,

The invention relates to improvements in machine tools. and more particularly to control dogs, which are adjustably mounted to act in connection with other parts to control the operation of the machine.

The object oi the invention is to provide a control dog of simple and improved construction which may be adjusted by the operator with a minimum of time and effort, and which is self-locking in position.

\Vith this object in view, the several features of the invention consist in the devices, combinations and arrangement of parts hereinafter described and claimed, and together with the advantages to be obtained thereby will be readily understood by one skilled in the art from the following description taken in connection with the accompanying drawings, in which Fig. 1 is a view in front elevation of a grinding machine embodying the present invention; Fig. 2 is a detail plan view partly in section of the dog, the slot in which it is mounted and a lever cooperating therewith. the parts being shown in operating position; Fig. 3 is a sectional view in left elevation of Fig. 2, the parts be ing shown in a different position; and Fig. 4 is a view similar to Fig. 2 somewhat more in detail with the dog lifted against the pressure of its spring for adjustment along the slot. For a more complete disclosure of the whole machine, reference may be had to the application of ldaxwell I. Mathewson for improvements in grinding machines, Serial No. 206917 filed on even date herewith.

The present embodiment of the invention in a grinding machine comprises a table dog which is adjustably mounted in a T-shapcd slot on the work supporting table of the machine. A plurality of dogs are mounted on the table and cooperate with a reversing lever mounted on a fixed portion of the machine to impart a reciprocatory movement to the table, the extent of which is determined by the positions of the dogs in the slot.

Referring more specifically to the drawings, the control dogs are indicated at 6 mounted in a T-shaped slot 8 which extends lengthwise of the work supporting table 10 of the machine. A reversing lever cooperating therewith is indicated at 12 pivoted at 14 on the machine frame.

The control dogs 6 which form the subject matter of the present invention, comprise an oblong block which is shaped to fit into the 1927. Serial No. 206,897.

main portion of the T-shaped slot and is provided at one end with a contact surface 16 adapted to engage with a corresponding surface on the reversing lever 12. Two projections which form a cross bar 18 are provided at the contact end of the block to engage with the undercut portions 20 of the slot and form a sliding pivot for the dog. The dog is nor mally secured against end movement along the slot by means of the gear teeth 22 which are formed on the opposite end of the block and are adapted to engage With a rack 24 in the bottom of the T-slot. A spring 26 secured to the block to bear against the undercut portion of the groove tends to rotate the dog about its pivot to hold the gear teeth 22 in engagement with the rack 24.

With this construction, the dog is self-locking in position since any pressure against the contact point will tend to swing the dog about the cross bar 18 and cause the gear teeth 22 to mesh firmly with the rack 24-. When on the other hand, pressure is applied to push the block in the opposite direction, the dog will tend to swing about the cross bar 18 to separate the gear teeth 22 so that they will slide over the teeth of the rack 24. The dog may be readily moved by the. operator in either direction to adjust the table travel by pulling the rear end of the dog forward to disengage the gear teeth and the rack.

The invention having been described, what is claimed is:

1. The combination in a machine tool of a member having an undercut slot, a rack on the member, and a dog provided with a pro jection engaging with the undercut portion of the slot to form a sliding pivot for the dog, gear teeth on the dog, and a contact surface on the dog placed so that pressure on the contact surface tends to swing the dog about its pivot to bring the gear teeth into locking engagement with the rack.

2. The combination in a machine tool of a member having an undercut slot, a rack on the member, a dog provided with a projection engaging with the undercut portion of the slot to form a sliding pivot for the dog, gear teeth on the dog, a spring for holding the gear teeth yieldingly in engagement with the rack, and a contact surface on the dog placed so that pressure on the contact surface tends to swing the dog about its pivot to bring the gear teeth into locking engagement with the rack.

3. The combination in a machine tool of a member having a T-slot, a rack formed in the bottom of the slot, a dog provided with projections engaging With the undercut portion of the slot to form a sliding pivot for the dog, gear teeth on the dog, and a contact surface on the dog placed so that pressure on the con tact surface tends to swing the dog about its pivot to bring the gear teeth into locking engagement with the rack.

4. The combination in a machine tool of a member having" a T-slot. a rack formed in the bottom of the slot, and a dog comprising a body portion adapted to fit in the main portion o? the slot. a contact surface formed at one end of the dog project in: arms at the contact end of the dog emragiug with the undercut portions of the slot to form a sliding pivotfor the dog and gear teeth formed at the other end of the dog adapted to be brought.

into locking engagement With the rack by pressure on the contact surface.

5. The combination in a machine tool of a member having a T-shaped slot, a rack formed in the bottom of the slot and a dog adjustably mounted in the slot comprising a block adapted to slide in the main portion of the slot, a contact surface formed at one end of the block, projections formed on the contact end of the block engaging with the undercut portions of the slot to form a sliding pivot for the dog, gear teeth formed on the other end of the block adapted to be brought into locking engagement with the rack by pressure on the contact surface, and spring means for holding the gear teeth yieldingjyly in engagement with the rack.

In testimony whereof I have signed my name to this specification.

ARTHUR BROW'N 

